


Moonlit Mirage

by luckystars1015



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Angst, Blue Lions Route spoilers, Bottom!Byleth, Dimitri x Byleth (Male), Dubious Consent, Emotional Manipulation, Hurt and comfort, M/M, Mainly just sex, Post Time Skip, Sexual Manipulation, Smut, student x professor relationship, top!dimitri
Language: English
Status: Completed
Published: 2019-10-30
Updated: 2019-10-30
Packaged: 2021-01-13 07:46:32
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,331
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21240632
Author URL: https://archiveofourown.org/users/luckystars1015/pseuds/luckystars1015
Summary: “Do you remember the night we kissed after the Battle of the Eagle and Lion?” Dimitri asks out of the blue.Remember? How could Byleth ever forget? But instead of admitting so, Byleth avoids Dimitri’s burning gaze and murmurs a quiet “no.”“Liar,” Dimitri accuses and swoops down to the capture professor’s lips in a searing kiss.





	Moonlit Mirage

Byleth awakens from a too long slumber wishing for one more moment of peace before the sunlight roused him through his eyelids. If Sothis could still talk to him, she would not waste a second to berate him for his laziness. His limbs twitch, desperate to move again. He jolts up as his body trembles at the memory of Lady Rhea’s draconic roar, her embers singeing the earth. 

“Holy shit! You’re still alive!” An unfamiliar voice calls out. “I thought for sure you’d be dead. I just fished you out of the river. And here I thought you would be the biggest Faudlan Carp I’d seen this century. I could have fed my family for a month.”

The stranger runs his eyes over Byleth’s form, perturbed by this man’s soft colored hair. Even his eyes were colored in the way grass must have been in heaven. 

Byleth doesn’t have time to stare back. He had an invasion to stop, his students to protect. He shoots up, startling the villager. “Point me to the way of the monastery!”

“You mean Garrech Mach?” The villager looks at Byleth like he had grown two heads. “That place has been abandoned for five years!”

The professor’s breath stops. ‘No! That was impossible!’ His feet move without his command, desperate to return to the place he had come to call home. 

“Wait! Only lowly thieves roam the monastery now! And I’ve heard a golden demon now hunts within those hallowed halls! You’re going to get yourself killed!!” But the villager’s warning falls upon deaf ears. 

——————

Byleth walks through the dilapidated structure of Garrech Mach, his heart sinking with each step. The air was ladened with dust and the stench of decay. The halls that were once filled with the constant chatter of students were void of any life. Not even vermin saw this place fit for their home. Eventually, he finds himself at the center of the church.

All at once, his eyes zero in on gold and his breath ceases, body paralyzed. It was _ him. _ Nothing seems real right now. Five years could not have possibly passed without his knowing. Sothis, this world’s goddess creator, manipulated the fabric of time. So how could time be so errant and slip through his hands like this? Step by step, he closed the distance between Dimitri and himself. 

The King of Fhirdiad tilts his head upwards and peers through long golden bangs. His one good eye does not register surprise, only submission and so much sadness. 

“Professor, have you come to join the ghosts that haunt me as well?” 

The professor of the Blue Lions clenches his fists, not believing the sight in front of him. Dimitri, his best student filled with so much hope and ambition had turned into _ this. _ Byleth would give anything to turn back time now—to stop fate’s cruel hand from robbing the light out of the royal’s eyes. 

Byleth kneels down in front of his lost student and reaches out a hand, but Dimitri does not take it. He still believes the professor to be a mere illusion—a trick his mind was playing to punish him for his sins. Byleth can no longer bear the distance and closes the gap himself, placing his hand on the sharp contour of Dimitri’s cheek. 

“I’m here now. Don’t worry anymore.” The warmth of the professor’s palm spreads through Dimitri’s being like a wildfire. For the first time in years, his heart beats like a human instead of a beast. 

A flash of hope ignites across the blonde’s face, but it flickers out of existence a moment later as the yells of thieves echo through the crumbling walls of the monastery. This moment had been lost to the sands of time. 

———

Dimitri fights like a rabid beast, tearing through the pack of thieves with no remorse. A young boy, who even Byleth knew had nothing on his side but poor luck, cowered before the golden demon ripping through his comrades like paper. The goddess vessel tells the boy to run as he stands in Dimitri’s way, preventing the beast from claiming another victim. 

This was not the Dimitri that Byleth knew. This was some bloody monster who had never seen the light of day. What happened to the student that would bear the weight of every casualty on his tired shoulders? The one who always tried to find a way to avoid needless bloodshed?

“What happened to you?!” Byleth holds his sword up against the last person he had ever wanted to fight. 

“The Dimitri you knew died five years ago!! No. The true Dimitri died the day his family was slaughtered in front of his eyes. I am nothing but a walking corpse.”

The more helpless Byleth feels, the tighter he grips his sword. It is the only anchor he has left in this foreign landscape. 

Dimitri looks past Byleth at the retreating band of thieves. His hands itch to spill tainted blood. “You are either with me or against me, Professor,” he says with a voice as cold as ice. 

Before Byleth can choose, the hands of fate choose for him in the arrival of familiar faces. Mercedes comes bounding into the church like a guardian angel with a mission. “They’re over here! The professor and Dimitri are still alive! The goddess has blessed us with a miracle!”

One by one his former students file in. Many of them are taller and more mature than he could have expected. They really did grow up in a blink of an eye. His only regret is that he was not there to see them do so. 

——

Mercedes is right. Only a goddess given miracle could have had the Blue Lions joining together after so much time and tragedy had passed. It was a promise they all somehow managed to fulfill. 

Dimitri barely partakes in the celebration, leaving abruptly after someone asks where Dedue was. Gilbert is the bearer of bad news as he explains that the loyal guard had sacrificed his life for his Highness’s sake five years ago. The air turns solemn afterwards and Byleth calls it a night for the sake of his students. What a reunion indeed. 

———

A month passes and with it, another campaign. Thanks to the diligence of Gilbert, they are able to gather more resources and soldiers. Byleth does what he knows best. He resumes teaching classes, but it seems he has more to learn from the students than he has to teach. 

Dimitri’s absence is palpable every time he walks into the classroom. He refuses any and all invitations for meals and tea. He only stands there in front of the rubble of the church. Byleth knows he is not praying to the goddess. He is holding conversations with the dead. The professor wants so desperately to pull Dimitri out of the dark, but how does one save somebody who does not want to be saved? 

The moon rises to bathe in the sea of stars above. Byleth cannot fall asleep on this windy night. Instead he walks around the monastery, his hand running along the crumbling walls. The professor was not a believer of ghosts, but he would not be surprised if there were some walking alongside with him tonight. 

Somehow, his waywardness has landed him right in front of Dimitri’s room. It was only a guess, but this was the royal wing of the dormitory and just one room had the flickering of a candlelight peeking through the door slits. 

He knocks on the door only to have it open for him as the weight of his hand pushes it open. 

“I-I’m sorry. I hadn’t known the lock was broken.” Guess the thieves found this place before he did. The room was bare, but Byleth had an inkling that nothing was there to begin with. Only a map was pinned to the wall as Dimitri’s lance laid within arm’s reach of the noble. The Blue Lion royal said nothing to this late night invasion as he sat immobile in a chair. 

Byleth continues to stand at the entryway, not daring to step further into the lion’s den. “I want to apologize before for the thieves. I know it wasn’t right to let them go like that. But the remaining lot were nothing more than kids—“

Dimitri slams his fist into the table next to him, splintering the wood. “SHUT UP!!”

Byleth cannot believe that his student would ever raise his voice like this. He finally makes his way in front of Dimitri. The goddess vessel stands his ground and looks Dimitri dead in the eyes. “I am still your professor and you will _ not _ speak to me like that,” he says in a definitive tone. 

“_ Oh really?” _ Dimitri jeers. He stands and walks towards Byleth, forcing him to retreat until his back hits the wall. Fhirdiad’s true king slams the door behind his professor shut, blocking the only possible escape route. 

Byleth is pinned between the wall and Dimitri’s foreboding form. In the five years, his student had grown taller, his armed figure seemed to dwarf Byleth in comparison. The goddess vessel feels like a trapped animal awaiting his execution. Dimitri’s eyes are flooded with a beast-like rage. 

The professor shuts his eyes tightly, wondering if this was how he was to meet his end: at the hands of his beloved student. Dimitri holds Byleth’s chin between his fingers and lifts his face, forcing the captured man to look him the eyes. A cold blue fire burns within those blue orbs. 

“Do you remember the night we kissed after the Battle of the Eagle and Lion?” Dimitri asks out of the blue. 

Remember? How could Byleth ever forget? Many of their classmates were not much drinkers. But Sylvain’s silver tongue had convinced the two to drink one cup and then another after that. On and on, the cycle repeated until most students fell asleep on the table or the floor. 

Byleth had left around his third mug, deciding that alcohol poisoning was not the best way to end the night. Dimitri follows him soon after his fourth mug, and the two settle in the gazebo hidden from any prying eyes. 

The two talked excitedly about the highlights of the battle, praising one another’s battle prowess. With his inhibitions dissolved by the alcohol, Byleth’s eyes could not help but fall upon the prince’s captivating lips. A still silence fell upon them when they failed to focus on anything but the strange chemistry sparking between them. 

Byleth reminded himself that he was a professor above all else and moved to excuse himself. Unfortunately, Dimitri had other plans for him. The prince bravely closed the distance between their lips and drags his professor back down to him. 

They kiss for what seemed like ages. Byleth was sober enough to understand what was happening. He was undoubtedly kissing his student who was heir to the kingdom. However, he was just drunk enough to not want to separate because it had just felt _ so good. _Under the soft graces of the moon, the two moved their lips against each other. As Byleth relished in the softness of Dimitri’s lips, his student brazenly licked their professor’s bottom lip, beckoning for entrance. 

Byleth was shocked enough to remember their positions and pushed Dimitri away by his shoulders. He quickly separated himself from the prince and stumbled away drunkenly into the night, the heat of Dimitri’s lips leaving his mouth tingling. 

The two returned to normal the next day in class, neither willing to acknowledge what had transpired under the moonlight. They incorrectly assumed that the other had forgotten due to their drunken stupor. 

Back in the present, Byleth avoids Dimitri’s burning gaze. The dim light of the lantern does not hide the heated flush that spreads across the professor’s face. 

“N-no.”

“_ Liar _,” Dimitri swoops down time steal a kiss. 

The kiss this time is not soft and tentative like that night so many moons ago. This one is searing, as if Dimitri were trying to burn Byleth alive. The rightful king shoves his tongue easily into the unguarded professor’s mouth. Dimitri takes and takes until Byleth’s knees go weak, only able to keep upright due to his student’s tight grip. 

Byleth is a seasoned warrior, but this is a new battlefield. Dimitri easily splits Byleth’s legs with his own as his thigh grinds against the professor’s growing hardness. Too much was happening all at once; this master tactician had no foresight to any of Dimitri’s oncoming attacks. 

Dimitri continues his campaign and explores the professor’s mouth with more fervor. He weakens Byleth’s defense even further as his tongue pushes and pulls against his professor’s own. Byleth’s lungs burn as he forgets how to breathe under the onslaught of his student’s passion. 

The royal Blue Lion cups his professor’s buttocks with both his hands in order to lift Byleth off the ground and carry him to the bed. He unceremoniously drops the professor onto the mattress and moves to his desk to rummage in his drawers. 

Byleth is finally able to breathe again. “Wait, Dimitri, I think we need to talk first before we—“

“You lost the chance to talk to me when you abandoned me for five years.” Dimitri’s voice rings harshly in Byleth’s ears. His words strike Byleth like an arrow. 

Dimitri finds a small vial of oil that Sylvain had given to him as a joke on his twenty-first birthday. He walks to the edge of the bed, peering down at his captive. The prince looms over the delectable form of his paralyzed professor. “Come on, Professor. I know you’re feeling this, too.” He drags a gloved finger across Byleth’s hard member, earning an unconstrained hiss from his teacher. 

Byleth doesn’t know what to do in the face of such impropriety. But this was the first time Dimitri had spoken to him outside the battlefield since he had found him broken and alone in the monastery. Perhaps this was his only chance to bridge the vast chasm that separates him and the wayward Dimitri. Maybe this was his one remaining option to save his wounded beast of a student. 

The goddess vessel falls back to the bed in submission. Dimitri wastes no time in removing his hands of his gloves and throws them onto the floor, the metal clunking as they land. Byleth burns with anticipation as his student removes the professor’s pants and undergarment. His erection springs up, proud and free while its master lay ashamed and exposed. 

Dimitri pours an ample amount of oil into his hand. Once he puts the vial back down, he links a long stripe on his clean hand and wraps it around Byleth’s hard member. Dimitri begins stroking his professor’s length as one oiled finger penetrates Byleth’s virgin asshole. Byleth’s abs grow taught at this foreign invasion as he lets out a small whimper. 

“Does it hurt?”

The professor is surprised by Dimitri’s concern. He had not completely transformed into a dastardly beast after all. “N-no,” Byleth stammers out as he reflexively tightens around Dimitri’s finger. 

“I’m going to start moving.” 

Byleth surprisingly begins to relax as the royal continued his ministrations. Dimitri massages his insides as he jerks off his professor. This was _so_ _not_ in the curriculum. Before long, he adds a second finger as Byleth whimpers at the burning stretch. Dimitri quickly distracts Byleth from the pain by wrapping his sinful mouth around the professor’s dick. 

The sword wielder yelps as his hands come to dig into Dimitri’s hair and pulls his head upwards, urging him to stop. He could not allow His Highness to do something so shameful. But the noble Blue Lion is unrelenting. Dimitri’s dexterous fingers are not forgotten as he curls them against the one spot that has Byleth seeing stars behind eyelids. Unable to control his errant body, Byleth hips bucks upwards, forcing his dick deeper into Dimitri’s mouth. The professor shudders as he feels his student’s hot mouth take him in completely, his lips brushing against the base of his aching member. Byleth takes no notice of the third finger intruding his insides as the fire in his loins turn into magma, threatening to melt his insides. 

In the blink of an eye, the double onslaught of his nether regions ceases and the cold air licks his naked self. “I think it’s about time,” Dimitri says as he removed himself from the professor. 

Byleth does _ not _miss the comfortable heat that this great lord had gotten him addicted to. Dimitri unbuckles his pants and removes his aching and wet dick from its clothed prison. He is too impatient to disrobe himself completely and keeps his armor on. The prince takes up the vial once more and lathers his cock with ample amounts of oil. 

The professor licks his now dry lips as he zeroes in the large, weeping dick in His Highness’s grasp. Dimitri mistakes Byleth look of anticipation with worry. “Do not worry, I am clean. As if I would lay with some lowly peasant.” 

Dimitri closes the maddening distance between them and lifts Byleth’s hips off the bed. He lines his cock at Byleth’s entrance. Silence fills the space in between them. Byleth takes the last leap and pulls Dimitri down into a searing kiss, his sign of accepting his student, sins and all. The voices in Dimitri’s head finally stop as he pushes himself into his professor’s wet heat. 

Byleth immediately clamps down onto Dimitri’s hard length, relishing in the pleasurable burn of his walls stretching to encompass him. The air between them fill with each other’s harsh, heated breath. Dimitri tentatively draws back until only his head remains inside. In the next breath, he slams back into Byleth, completely sheathing himself in his tight walls. 

Dimitri continues his unforgiving pace, pulling out and shoving himself into Byleth relentlessly. The beast had drawn its head out once more. Byleth loses all sense and reasoning as deep moans escape his unguarded lips. It feels like lightning has struck him every time Dimitri slams his dick into his prostate. Nothing in this world exists except the current of pleasure running through their bodies. 

Byleth’s hips begin to ache under the Dimitri’s unrelenting force. “I can’t—I can’t—” The goddess vessel is unable to form a coherent sentence as his climax rips through him. His toes curl and his body grows taught as a bow as orgasm ripples through him. Long ribbons of come shoot out, staining Dimitri’s armor, but the royal does not cease. 

Dimitri continues to fuck Byleth through his orgasm until his professor’s sinful body catapults the student into his own climax. Dimitri does not remove himself as he cums, filling Byleth to the brim with his semen. 

The Blue Lion noble finally comes down from his high to discover his professor slipping into a drowsy state. However, he does not wish to stop. He reluctantly removes himself from Byleth to take off his armor. He sighs in relief as the cold air caresses his heated, sweaty skin. 

He also disrobes Byleth of the rest of his clothes. The pair run their eyes along each other’s nude form. There are many more scars splattered across Dimitri’s body and Byleth is saddened by the thought that he could have prevented them if he had only been by his student’s side. 

Dimitri does not like the look of pity that paints his professor’s face. He flips Byleth onto his stomach without warning. “I’m going to keep going.” Byleth neither has the strength nor the desire to stop him. 

The noble quickly shoves himself back into Byleth, taking deep satisfaction in the wet squelch due to his seed. He was going to stain the professor with his undeniable mark. From this day onwards, Dimitri would pour himself into the professor so much so that every inch of Byleth’s lovely form would irrevocably belong to him. 

**Author's Note:**

> I yearn for your reviews like Dimitri yearns to avenge his family


End file.
